I agree processes are the challenge. S&OP planning is much talked about but seldom practised. Forecasts are often just wish lists i.e they don't last as long as the lead time, and go to the wind when a real order comes in so there is then no consistent company game plan., Its a trade off between the efficiency of stability and the cost of turning away disruptive business, So don't be a busy fool- but tis OK to premium price to be reactive /give a high service. Ultimately your customers and suppliers also need to make the same choice about their costs and service. Is there any point having a sales forecast if its not shared with the vendors, and not the basis of the production plan for a frozen period?
Ax, like most erp system, can generate messages- in my experience many users ignore these but to really understand what is happening review of messages is necessary. Another area where the functionality is improved at Ax 2012.
A real problem is that mrp believes what you tell it e.g. with regard to lead time and capacity and this its plan should be a. correct and b. consistent at all levels.
Then we would not need a master scheduler! the problem is that in the real world the rules and policies change daily - we tell the system the raw material LT is 5 days but we know we can expedite if we pay more or collect it with our own transport. We tell the system the sales lead time is 5 days but we take a rush order because we know we can work overtime. We tell the system the vendor confirmed full delivery but it turn up short on the wrong date.
We know there is fire drill on Thursday and that machine 2 will run slow till the next pm, and the customer is happy to accept partial shipments, that the customer cancelled an order, and we firm our plan accordingly and then protect it with some time fences.
We also manage that noise by forecasts minimums, buffer stock etc. Its not practical to manage coverage parameters and policies order by order. When you pose mrp a dilemma i.e. a firm plan to make to tomorrow it believes you. But it knows you don't have capacity or materials - but hey you are the master planner so it believes you and plans to those formed sales and production orders. But its not happy. So it tries to help by bombarding you with messages to remind you to square the circle and to ensure you have not made a mistake or missed something . So it sends you an expedite message to helpfully tell you that you should have ordered this last week. That might help you to focus on what to expedite. What fi you can't? then it also sends you another message to take a different action like redating the order. So its possible you will get a planned order and a message to delete it. Unless you are clear on our policies and changes that can be confusing. Once you understand what they system is trying to do based on what polices and supplied demand sit ahs then the message can be a great aid.
However they can also be a noise- you need a delivery date this week to make next week so you notionally put Wed on the order and as long as it comes this week you don't care which day but the system does and sends you a reschedule message. You round up the quantity to save transport costs but the system doe snot understand why and suggests you amend it. Plan stability and sensible mrp parameters e.g for negative and positive days reduce the noise but there will always be the last mile for the master scheduler to mange - that is why he's the master scheduler not Ax.
Many companies either don't run mrp or only run it in expedite mode with a shortage report for these reasons. ABC, an empowered master scheduler, frozen forecasts, an agreed S&Op plan , sensible fences, CATP /ATP etc are a foundation that will show what a system like Ax can do. For many industries life is not so straightforward - but few understand the real cost of not having stable master plans.
Good luck. I'm interested to hear how you get on.
